A semiconductor device described in Japanese Patent Application Publication No. 2015-233035 includes a semiconductor substrate, a first metal layer, a protective insulating film, and a second metal layer. The first metal layer covers a surface of the semiconductor substrate. The protective insulating layer covers a part of a surface of the first metal layer. The second metal layer is constituted of a metal (Ni) different from a metal (AlSi) of the first metal layer. The second metal layer covers the surface of the first metal layer in a range not covered by the protective insulating film. Further, the second metal layer is in contact with an edge portion of the protective insulating film. Thus, the edge portion of the protective insulating film is a triple-contact portion where the first metal layer, the second metal layer, and the protective insulating film are in contact with each other.
Japanese Patent Application Publication No. 2017-054928 describes a semiconductor device including a contact plug. The contact plug is constituted of a metal and is provided to penetrate an interlayer insulating film. The contact plug is in contact with a semiconductor substrate. Surfaces of the interlayer insulating film and the contact plug are covered by a metal layer.